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Rassbach J, Hilsberg N, Haensch VG, Dörner S, Gressler J, Sonnabend R, Semm C, Voigt K, Hertweck C, Gressler M. Non-canonical two-step biosynthesis of anti-oomycete indole alkaloids in Kickxellales. Fungal Biol Biotechnol 2023; 10:19. [PMID: 37670394 PMCID: PMC10478498 DOI: 10.1186/s40694-023-00166-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/06/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND Fungi are prolific producers of bioactive small molecules of pharmaceutical or agricultural interest. The secondary metabolism of higher fungi (Dikarya) has been well-investigated which led to > 39,000 described compounds. However, natural product researchers scarcely drew attention to early-diverging fungi (Mucoro- and Zoopagomycota) as they are considered to rarely produce secondary metabolites. Indeed, only 15 compounds have as yet been isolated from the entire phylum of the Zoopagomycota. RESULTS Here, we showcase eight species of the order Kickxellales (phylum Zoopagomycota) as potent producers of the indole-3-acetic acid (IAA)-derived compounds lindolins A and B. The compounds are produced both under laboratory conditions and in the natural soil habitat suggesting a specialized ecological function. Indeed, lindolin A is a selective agent against plant-pathogenic oomycetes such as Phytophthora sp. Lindolin biosynthesis was reconstituted in vitro and relies on the activity of two enzymes of dissimilar evolutionary origin: Whilst the IAA-CoA ligase LinA has evolved from fungal 4-coumaryl-CoA synthetases, the subsequently acting IAA-CoA:anthranilate N-indole-3-acetyltransferase LinB is a unique enzyme across all kingdoms of life. CONCLUSIONS This is the first report on bioactive secondary metabolites in the subphylum Kickxellomycotina and the first evidence for a non-clustered, two-step biosynthetic route of secondary metabolites in early-diverging fungi. Thus, the generally accepted "gene cluster hypothesis" for natural products needs to be reconsidered for early diverging fungi.
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Affiliation(s)
- Johannes Rassbach
- Faculty of Biological Sciences, Pharmaceutical Microbiology, Friedrich Schiller University Jena, Winzerlaer Strasse 2, 07745, Jena, Germany
- Pharmaceutical Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Winzerlaer Strasse 2, 07745, Jena, Germany
| | - Nathalie Hilsberg
- Faculty of Biological Sciences, Pharmaceutical Microbiology, Friedrich Schiller University Jena, Winzerlaer Strasse 2, 07745, Jena, Germany
- Pharmaceutical Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Winzerlaer Strasse 2, 07745, Jena, Germany
| | - Veit G Haensch
- Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Adolf-Reichwein-Strasse 23, 07745, Jena, Germany
| | - Sebastian Dörner
- Faculty of Biological Sciences, Pharmaceutical Microbiology, Friedrich Schiller University Jena, Winzerlaer Strasse 2, 07745, Jena, Germany
- Pharmaceutical Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Winzerlaer Strasse 2, 07745, Jena, Germany
| | - Julia Gressler
- Faculty of Biological Sciences, Pharmaceutical Microbiology, Friedrich Schiller University Jena, Winzerlaer Strasse 2, 07745, Jena, Germany
- Pharmaceutical Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Winzerlaer Strasse 2, 07745, Jena, Germany
| | - Robin Sonnabend
- Faculty of Biological Sciences, Pharmaceutical Microbiology, Friedrich Schiller University Jena, Winzerlaer Strasse 2, 07745, Jena, Germany
- Pharmaceutical Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Winzerlaer Strasse 2, 07745, Jena, Germany
| | - Caroline Semm
- Faculty of Biological Sciences, Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, 07743, Jena, Germany
- Jena Microbial Resource Collection (JMRC), Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Adolf-Reichwein-Strasse 23, 07745, Jena, Germany
| | - Kerstin Voigt
- Faculty of Biological Sciences, Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, 07743, Jena, Germany
- Jena Microbial Resource Collection (JMRC), Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Adolf-Reichwein-Strasse 23, 07745, Jena, Germany
| | - Christian Hertweck
- Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Adolf-Reichwein-Strasse 23, 07745, Jena, Germany
- Faculty of Biological Sciences, Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, 07743, Jena, Germany
| | - Markus Gressler
- Faculty of Biological Sciences, Pharmaceutical Microbiology, Friedrich Schiller University Jena, Winzerlaer Strasse 2, 07745, Jena, Germany.
- Pharmaceutical Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Winzerlaer Strasse 2, 07745, Jena, Germany.
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Pichler G, Muggia L, Carniel FC, Grube M, Kranner I. How to build a lichen: from metabolite release to symbiotic interplay. THE NEW PHYTOLOGIST 2023; 238:1362-1378. [PMID: 36710517 PMCID: PMC10952756 DOI: 10.1111/nph.18780] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/28/2022] [Indexed: 06/18/2023]
Abstract
Exposing their vegetative bodies to the light, lichens are outstanding amongst other fungal symbioses. Not requiring a pre-established host, 'lichenized fungi' build an entirely new structure together with microbial photosynthetic partners that neither can form alone. The signals involved in the transition of a fungus and a compatible photosynthetic partner from a free-living to a symbiotic state culminating in thallus formation, termed 'lichenization', and in the maintenance of the symbiosis, are poorly understood. Here, we synthesise the puzzle pieces of the scarce knowledge available into an updated concept of signalling involved in lichenization, comprising five main stages: (1) the 'pre-contact stage', (2) the 'contact stage', (3) 'envelopment' of algal cells by the fungus, (4) their 'incorporation' into a pre-thallus and (5) 'differentiation' into a complex thallus. Considering the involvement of extracellularly released metabolites in each phase, we propose that compounds such as fungal lectins and algal cyclic peptides elicit early contact between the symbionts-to-be, whereas phytohormone signalling, antioxidant protection and carbon exchange through sugars and sugar alcohols are of continued importance throughout all stages. In the fully formed lichen thallus, secondary lichen metabolites and mineral nutrition are suggested to stabilize the functionalities of the thallus, including the associated microbiota.
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Affiliation(s)
- Gregor Pichler
- Department of BotanyUniversity of InnsbruckSternwartestraße 156020InnsbruckAustria
| | - Lucia Muggia
- Department of Life SciencesUniversity of TriesteVia L. Giorgieri 1034127TriesteItaly
| | | | - Martin Grube
- Institute of BiologyUniversity of GrazHolteigasse 68010GrazAustria
| | - Ilse Kranner
- Department of BotanyUniversity of InnsbruckSternwartestraße 156020InnsbruckAustria
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Khakhar A. A roadmap for the creation of synthetic lichen. Biochem Biophys Res Commun 2023; 654:87-93. [PMID: 36898228 DOI: 10.1016/j.bbrc.2023.02.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023]
Abstract
Lichens represent a charismatic corner of biology that has a rich history of scientific exploration, but to which modern biological techniques have been sparsely applied. This has limited our understanding of phenomena unique to lichen, such as the emergent development of physically coupled microbial consortia or distributed metabolisms. The experimental intractability of natural lichens has prevented studies of the mechanistic underpinnings of their biology. Creating synthetic lichen from experimentally tractable, free-living microbes has the potential to overcome these challenges. They could also serve as powerful new chassis for sustainable biotechnology. In this review we will first briefly introduce what lichen are, what remains mysterious about their biology, and why. We will then articulate the scientific insights that creating a synthetic lichen will generate and lay out a roadmap for how this could be achieved using synthetic biology. Finally, we will explore the translational applications of synthetic lichen and detail what is needed to advance the pursuit of their creation.
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Affiliation(s)
- Arjun Khakhar
- Biology Department, Colorado State University, 251 West Pitkin Drive, Fort Collins, CO, 80525, USA.
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Singh G, Calchera A, Schulz M, Drechsler M, Bode HB, Schmitt I, Dal Grande F. Climate-specific biosynthetic gene clusters in populations of a lichen-forming fungus. Environ Microbiol 2021; 23:4260-4275. [PMID: 34097344 DOI: 10.1111/1462-2920.15605] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 12/16/2022]
Abstract
Natural products can contribute to abiotic stress tolerance in plants and fungi. We hypothesize that biosynthetic gene clusters (BGCs), the genomic elements that underlie natural product biosynthesis, display structured differences along elevation gradients. We analysed biosynthetic gene variation in natural populations of the lichen-forming fungus Umbilicaria pustulata. We collected a total of 600 individuals from the Mediterranean and cold-temperate climates. Population genomic analyses indicate that U. pustulata contains three clusters that are highly differentiated between the Mediterranean and cold-temperate populations. One entire cluster is exclusively present in cold-temperate populations, and a second cluster is putatively dysfunctional in all cold-temperate populations. In the third cluster variation is fixed in all cold-temperate populations due to hitchhiking. In these two clusters the presence of consistent allele frequency differences among replicate populations/gradients suggests that selection rather than drift is driving the pattern. We advocate that the landscape of fungal biosynthetic genes is shaped by both positive and hitchhiking selection. We demonstrate, for the first time, the presence of climate-associated BGCs and BGC variations in lichen-forming fungi. While the associated secondary metabolites of the candidate clusters are presently unknown, our study paves the way for targeted discovery of natural products with ecological significance.
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Affiliation(s)
- Garima Singh
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany
| | - Anjuli Calchera
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany
| | - Meike Schulz
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany
| | - Moritz Drechsler
- Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, Frankfurt, 60438, Germany.,Department Natural Products in Organismic Interactions, Max-Planck-Institute for Terrestrial Microbiology, Marburg, 35043, Germany
| | - Helge B Bode
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany.,Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, Frankfurt, 60438, Germany.,Department Natural Products in Organismic Interactions, Max-Planck-Institute for Terrestrial Microbiology, Marburg, 35043, Germany.,Buchmann Institute for Molecular Life Sciences, Goethe Universität Frankfurt, Frankfurt, 60438, Germany
| | - Imke Schmitt
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany.,Institute of Ecology, Evolution and Diversity, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, Frankfurt, 60438, Germany
| | - Francesco Dal Grande
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany
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Pichler G, Candotto Carniel F, Muggia L, Holzinger A, Tretiach M, Kranner I. Enhanced culturing techniques for the mycobiont isolated from the lichen Xanthoria parietina. Mycol Prog 2021; 20:797-808. [PMID: 34720793 PMCID: PMC8550697 DOI: 10.1007/s11557-021-01707-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/01/2021] [Accepted: 04/28/2021] [Indexed: 02/08/2023]
Abstract
Lichens and their isolated symbionts are potentially valuable resources for biotechnological approaches. Especially mycobiont cultures that produce secondary lichen products are receiving increasing attention, but lichen mycobionts are notoriously slow-growing organisms. Sufficient biomass production often represents a limiting factor for scientific and biotechnological investigations, requiring improvement of existing culturing techniques as well as methods for non-invasive assessment of growth. Here, the effects of pH and the supplement of growth media with either D-glucose or three different sugar alcohols that commonly occur in lichens, D-arabitol, D-mannitol and ribitol, on the growth of the axenically cultured mycobiont isolated from the lichen Xanthoria parietina were tested. Either D-glucose or different sugar alcohols were offered to the fungus at different concentrations, and cumulative growth and growth rates were assessed using two-dimensional image analysis over a period of 8 weeks. The mycobiont grew at a pH range from 4.0 to 7.0, whereas no growth was observed at higher pH values. Varying the carbon source in Lilly-Barnett medium (LBM) by replacing 1% D-glucose used in the originally described LBM by either 1%, 2% or 3% of D-mannitol, or 3% of D-glucose increased fungal biomass production by up to 26%, with an exponential growth phase between 2 and 6 weeks after inoculation. In summary, we present protocols for enhanced culture conditions and non-invasive assessment of growth of axenically cultured lichen mycobionts using image analysis, which may be useful for scientific and biotechnological approaches requiring cultured lichen mycobionts. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11557-021-01707-7.
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Affiliation(s)
- Gregor Pichler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Fabio Candotto Carniel
- Department of Life Sciences, University of Trieste, Via Giorgieri 10, 34127 Trieste, Italy
| | - Lucia Muggia
- Department of Life Sciences, University of Trieste, Via Giorgieri 10, 34127 Trieste, Italy
| | - Andreas Holzinger
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Mauro Tretiach
- Department of Life Sciences, University of Trieste, Via Giorgieri 10, 34127 Trieste, Italy
| | - Ilse Kranner
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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Diversity and Physiological Characteristics of Antarctic Lichens-Associated Bacteria. Microorganisms 2021; 9:microorganisms9030607. [PMID: 33804278 PMCID: PMC8001610 DOI: 10.3390/microorganisms9030607] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 12/23/2022] Open
Abstract
The diversity of lichen-associated bacteria from lichen taxa Cetraria, Cladonia, Megaspora, Pseudephebe, Psoroma, and Sphaerophorus was investigated by sequencing of 16S rRNA gene amplicons. Physiological characteristics of the cultured bacterial isolates were investigated to understand possible roles in the lichen ecosystem. Proteobacteria (with a relative abundance of 69.7–96.7%) were mostly represented by the order Rhodospirillales. The 117 retrieved isolates were grouped into 35 phylotypes of the phyla Actinobacteria (27), Bacteroidetes (6), Deinococcus-Thermus (1), and Proteobacteria (Alphaproteobacteria (53), Betaproteobacteria (18), and Gammaproteobacteria (12)). Hydrolysis of macromolecules such as skim milk, polymer, and (hypo)xanthine, solubilization of inorganic phosphate, production of phytohormone indole-3-acetic acid, and fixation of atmospheric nitrogen were observed in different taxa. The potential phototrophy of the strains of the genus Polymorphobacter which were cultivated from a lichen for the first time was revealed by the presence of genes involved in photosynthesis. Altogether, the physiological characteristics of diverse bacterial taxa from Antarctic lichens are considered to imply significant roles of lichen-associated bacteria to allow lichens to be tolerant or competitive in the harsh Antarctic environment.
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